Sunday, December 16, 2012

Some Pattern Change Thoughts ! What can we expect for the rest of Winter heading into January and February !

Date Issued:
12-16-12 .... Sunday AM

Discussion: For The M/A and NE States.
Some pattern change thoughts and the rest of our 2013 winter season.
Expect a Colder and snowy pattern to develop for much of January and February !

Good morning folks,

It's time to talk about some mid and long range thoughts for the M/A and NE. So far the month of December is panning out pretty well with my winter forecast call. I never seen the month of December being anything special for the cold and snow lovers crowd, and advertised both January and February being the time frame for much of our snow and cold in the M/A and Northeast.

As we all know, the first half of December has been quite mild over the Eastern CONUS. Both the Atlantic and Arctic signals have been sound and favorable, but the Pacific signal which has been bad (-PNA) is driving the overall pattern. As we head into the second half of this month, some gradual changes will begin to occur, as the Pacific signal relaxes some, and heads more to a neutral signal.

With a slightly negative NAO and AO signal continuing and a better Pacific pattern developing, I do expect temperatures to return to near and slightly below normal values here in the Eastern CONUS. With a very mild first half of the month and near to slightly colder during the second half, I still expect overall temps to finish at +1.0 F to + 3.0 F here in the Delaware Valley. I'm going with the chance for a minor snow event or 2, mainly between Christmas and New Years to close out the month. Minor event meaning, 4" or less. The second half of December is nothing more than a typical seasonal step down, and at best, a gradual pattern change towards the last week of the month.

So those forecasters and METS who were screaming that a pattern change is coming near mid-month.......... sorry Fail. A continued bad PAC signal, mild temps, and continued Lake Cutters, is not a pattern change. The overall u/l H5 pattern has not changed, and we are only seeing what I call a gradual seasonal step down heading into the second half of December.

My January/February 2013 thoughts:

This is when I'm forecasting the real pattern change to occur ! We should see the process get underway during the first half of the month and by the second half, the cold and snow lovers will rejoice ! The blocking pattern we seen back in October and November, will once again return and dominate. The Pacific signal will become much better and flip to a more Neutral to POS PNA. This will result in a cold and stormy pattern for the East and a milder and less active pattern out west.

Overall temps will average slightly below normal at -1.0 F to -3.0 F and snowfall should be near to above normal, for both the M/A and NE States. Once this pattern change occurs during the first half of January, I do expect this to continue for a solid 4 to 6 week period.

So with that being said, February should also result in a cold and snowy pattern here in the East. Our biggest snow threats will come between mid January into much of February. Expect 1 or 2 big snow events to produce 6"+ snow amounts over the Mid-Atlantic States and several 6"+ Snowstorms in New England.

In addition, our minor to moderate snow events for both January and February, will be associated with several northern branch style clippers. I also expect a couple of southern branch systems, associated with a developing STJ. This will result in overrunning snow and ice events for the Southern States, The M/A, and NE regions.

Take Care,


Well Red said...

Sounds good, John. Can't tell you how long I have been waiting for someone to tell me about some snow in the MA.

i will be skiing in V on 1/18 - hopefully it will be cold enough with enough white stuff on the ground to get in a couple of runs down the mountain.

Andrew Skaggs said...

You're expecting more snow in the south because of this too, right?

Anonymous said...

thanks for sharing.